Photographic processing apparatus



g- 15, 1967 H. E. ERIKSON 3,335,652

PHOTOGRAPHIC PROCESSING APPARATUS Filed Jan. 29, 1965 5 Sheets-Sheet l H. E. ERIKSON PHOTOGRAPHI C PROCESS ING APPARATUS Aug. 15, 1967 3 Sheets-Sheet 2 INVENTOR %u M14) BY M c MV/X 71 Filed Jan. 29, 1965 ATTORNEYS 15, 1i967 H. E. ERIKSON 3,335,652

PHOTOGRAPHIC PROCESS ING APPARATUS Filed Jan. 29, 1965 3 Sheets-Sheet 5 INVENTOR ATTORNEYS United States 3,335,652 PHOTOGRAPHIC PROCESSING APPARATUS Herman E. Erilrsori, Winchester, Mass, assignor to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware Filed Jan. 29, 1965, Ser. No. 429,079 7 Claims. (Cl. 95-89) ABSTRACT OF THE DISCLQSURE In the processing of photographic products according to a well-known diffusion transfer process, a fluid reagent is spread between a pair of liquid-confining sheets to effect processing of one or both sheets. It has been found convenient in commercial forms of photographic film units embodying the diffusion transfer process to supply the liquid processing agent in frangible containers positioned between the sheets. The container is ruptured to release the processing liquid, and the latter is spread in a uniformly thin layer between the sheets by advancing the film assembly comprising the sheets with the container therebetween through a pair of pressure-applying members such as elongated, juxtaposed rollers. The rollers are normally provided as a portion of photographic processing apparatus which provides the necessary mechanical elements for effecting processing of the film assembly or unit.

It is essential for optimum processing conditions that substantially all of the liquid-processing agent be forced out of the container wherein it is supplied and spread in a layer of predetermined and uniform thickness between the sheets of the film unit. One of the principal factors influencing these conditions is the amount of compressive force applied to the film unit as it is drawn between the pressure rolls. Since the film unit itself is not of uniform thickness (being somewhat thicker, for example, in the area wherein the container is positioned between the sheets) it has been found convenient to apply a spring bias to one or both pressure rolls for resiliently urging the two together with a predetermined compressive force while permitting separation of the rolls by a greater amount when portions of the film unit having a larger thickness pass therethrough. In fact, a plurality of spring elements have been used to provide different biasing forces on the pressure rolls at various stages in the advancement of the film assembly.

Processing apparatus has been constructed in accordance with the principles outlined above which provides satisfactory processing of film units requiring a given compressive force for removing the fluid from the container and a second, known compressive force for providing a required, predetermined thickness of the liquid layer between the sheets. However, fihn units of different types, for example, those having paper and those having acetate film support layers, may require different compressive forces at various stages in the advancement of the film unit through the pressure rolls. Thus, a given processing apparatus, having a predetermined spring bias applied to the pressure rolls, would be suitable for processing film units only of that type requiring the particular compressive force of the rollers of said given apparatus.

It is a principal object of the present invention to provide processing apparatus for self-developing film units of the type which are processed by spreading a liquidprocessing agent in a layer of predetermined thickness between a pair of sheets of the unit and which may be used to process a plurality of different types of such film llnits which require different thicknesses of said liquid ayer.

It is a further object to provide photographic processing apparatus, including a pair of pressure-applying members through which a film unit is advanced to effect processing thereof, wherein means are provided for quickly and conveniently altering the thickness of a liquid layer distributed between a pair of sheets of the film unit by advancement thereof through said pressureapplying members.

Another object is to provide novel photographic processing apparatus having a pair of pressure rolls which are biased toward contacting engagement with one another and having means for selectively changing the bias to produce a consequent, predetermined change in the manner in which said apparatus acts on a film unit to effect processing thereof.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

FIGURE 1 is an exploded, perspective view of apparatus embodying the present invention with portions broken away;

FIGS. 2-5 are enlarged, fragmentary, perspective views of a portion of the apparatus of FIGURE 1, showing the elements in a variety of positions;

FIG. 6 is a perspective view of a film unit of the selfdeveloping type which may be processed by the apparatus of the invention; and

FIG. 7 is an exploded, perspective view of certain elements of the apparatus shown from the side opposite that shown in FIGURE 1.

In US. Patent No. 2,638,828 is shown processing apparatus for use in processing a self-developing type of photographic film assembly. The apparatus includes a lighttight chamber within which the fihn assembly is placed prior to processing and a pair of pressure-applying members between which the assembly is advanced to effect spreading of a processing fluid between two liquid confining layers or sheets. After spreading of the processing liquid the assembly is stored in a second portion of the lighttight chamber for a predetermined processing period, it which time it is removed from the apparatus and the developed print and/ or negative is removed from the remainder of the assembly.

Apparatus of this type has been found especially useful in processing film assemblies used in making radiographic exposures, but is not limited to employment with such. Since most radiographic film, whether of the self-developing type or not, is held within a lighttight cassette during exposure, it is quite convenient to place the cassette within the aforementioned processing apparatus and advance the film assembly directly from the cassette through the pressure-applying members. It is to be understood, in connection with the following description, that certain constructional details of the illustrated embodiment of the invention may be influenced by the fact that the film unit to be processed may be extracted from a cassette during the processing operation. It is also pointed out that the above-mentioned US Patent No. 2,63 8,828 includes a detailed description of a basic form of processing apparatus of a type wherein the present invention may be incorporated.

Referring now to the drawings, and more particularly to FIGURE 1, there is shown the basic constructional elements of a form of photographic processing apparatus adapted to effect processing of a photographic film unit in a manner which will be later described in more detail. The apparatus includes a rigid frame having two sides in the nature of spaced, parallel wall members. The frame may conveniently be of unitary construction, or the wall members may be constructed separately and rigidly attached to other fixed elements of the apparatus. The wall members, denoted generally by the reference numerals and 12, are of like construction and each includes a forwardly extending portion, numbered 14 and 16 respectively, and rear wall portions 18 and 20 which may be seen to extend to a higher vertical plane than forwardly extending portions 14 and 16. Lower pressure roll 22 includes an axle or spindle means 24 extending fixedly from each end thereof and mounted for rotation in appropriate bearing means 26 and 28 which are provided on forwardly extending portions 14 and 16, respectively, of the rigid frame. Spindle 24 is connected to output shaft 30 of conventional electric motor 32, where by operation of the motor produces rotation of lower roll 22. An appropriate gear train 33 may be provided between spindle 24 and output shaft 30 to provide a desired speed of rotation and torque for lower roll 22 in response to operation of motor 32.

Upper pressure roll 34 includes second spindle means 36 extending from each end thereof and journaled for rotation in bearing means 38 and 40 provided on end portions of a first set of arms 42 and 44, respectively. Arm 42 is pivotally mounted upon rear wall portion 18 by means of shaft 46 which extends through opening 48 in arm 42 and opening 50 in wall portion 18 and is secured by nut 52. Arm 44 is pivotally mounted in like manner upon rear wall portion 20 by means of shaft 54, which extends through opening in rear wall portion 20 and is secured by nut 56. A second set of arms, numbered 58 and 60, are also provided on each side of the apparatus, and include openings 62 and 64, respectively, through which shafts 46 and 54 pass to mount the second set of arms for pivotal movement with respect to the frame about the same axis as the first set of arms. Second arms 58 and include, at the ends thereof opposite the pivotal mounting, downwardly extending portions 66 and 68 which carry, at the lower ends thereof, inwardly extending cars 70 and 72. Openings 74 and 76 extend through ears 70 and 72, respectively, and serve as a means for mounting lift bar 78 fixedly between second arms 58 and 60.

Rotatable shaft 80 extends across the apparatus in parallel relation to lift bar 78. One end 82 of shaft 88 extends rotatably through an opening provided for that purpose in a portion of wall member 18. The other end 84 of shaft 80 is keyed or otherwise afiixed to lever 86, with an intermediate portion of shaft 80 passing through an appropriate opening or bearing means in wall portion 12 of the rigid frame. Extending fixedly from portions of shaft 80 intermediate of wall members 10 and 12 are fingers 88 and 90, having extremities 92 and 94, respectively, which extend to predetermined portions under lift bar 78. It may thus be seen that depression of manually engagea-ble portion 96 of lever 86 will rotate shaft 80, which will result in lifting of extremities 92 and 94 of fingers 88 and 90, respectively. This movement of fingers 88 and will raise lift bar 78, which in turn will rotate second arms 58 and 60 in a clockwise direction, as seen in FIGURE 1, about their respective pivotal mountings upon shafts 46 and 54. Sufiicient clearance is allowed between lift bar 78 and the lower edges of wall members 10 and 12 to allow raising and lowering of bar 78. The terms elevated, upper, lower and the like are used in the present description to apply to the positions of lift bar 78 and associated elements movable therewith.

Also keyed to shaft 80 (in addition to lever 86) is hook 98 having end portion 100 which is adapted to be engaged by latch 102. The latter is pivotally mounted upon fixed bracket 104 by means of pin 106, and biased for rotation toward lever 86 by spring 108. As portion 96 of lever 86 is depressed, shaft 80 is rotated, causing like rotation of hook 98 with end portion 100 thereof moving upward. The end portion engages protruding portion 118 of latch 102, causing the latter to rotate against the bias of spring 188, as end portion 100 continues to move upward in contact with portion 110. When hook 98 has been rotated sufiiciently, end portion 100 will override protruding portion 110, spring 108 will cause counter-rotation of latch 102 and hook 98 will be engaged thereby. It is to be noted that the weight of second arms 58 and 60 and that of lift bar 78 will bear on extremities 92 and 94 of fingers 88 and 90 to maintain the latter in their lowermost position until lever 86 is depressed to move the elements to the upper position, wherein they are retained by hook 98 and latch 1112.

Turning now to a consideration of FIGS. 2-5, a fragmentary portion of the apparatus of FIGURE 1 is shown in greater detail to illustrate more clearly the operation of the present invention. Circular cam element 112 of variable radius is affixed to lift bar 78 by means of set screw 114, thereby allowing rotational adjustment of the cam with respect to the bar. First spring 116 is afiixed at one end by conventional means to first arm 42 and extends downwardly therefrom to engage plate 118 between the free end of the spring and upper surface 119 of ear 70. Thus, in the lower position of lift bar 78, arm 42 is biased away from arm 58 by spring 116. Ear 121 extends from arm 42 under arm 58 to limit movement of the former away from the latter, with spring 116 being slightly compressed when arm 58 is in the lower position. Stud extends through plate 118 into the spring to provide proper positioning of the plate and to serve as a rotational mounting therefor, as will be presently explained.

Second spring 122 is positioned between first arm 42 and enlarged end portion 123 of movable plunger 124. Anvil 126 is provided on upper surface 119 of car 70 in vertical alignment with end portion 123 of plunger 124. Fixed pin 130 extends radially from lift bar 78 through notch 132 in plate 118. Lever 134 extends through collar 136 and is afiixed to lift bar 78, as by being threaded therein. Lever 134 is shown in a first position in FIG. 2 and a second position in FIG. 3; the mechanism which limits movement of the lever between the two positions and the manner of adjustment thereof, will be explained later. Movement of lever 134 between its first and second positions will rotate lift bar 78, thereby moving cam 112 and pin 130. Movement of cam 112 changes the effective radius of lift bar 78 with respect to extremity 92 of finger 88. Since pin 130 is engaged in notch 132 of plate 118, movement of the' pin' between the positions of FIGS. 2 and 3 rotates the plate about an axis through stud 120, which is engaged by spring 116 as previously explained. In the FIG. 3 position, spacer element 154- of plate 118 is positioned between anvil 126 and end portion 123 of plunger 124. Although not shown in detail, it will be understood that the elements just described are duplicated on the opposite side of the apparatus to operate in conjunction with arms 44 and 60. For example, spring 117,

identical in structure and function to spring 116, is shown in FIGURE 1 extending downwardly from arm 44.

In FIG. 4 the elements are shown with lever 134, and thus the rotational position of lift bar 78, in the same position as in FIG. 2. In FIG. 4, however, lift bar 78 and the associated elements are shown in the elevated position, i.e., with shaft 80 rotated to the position wherein hook 98 is engaged by latch 102, as explained in connection with FIGURE 1. Elevation of lift bar 78 causes second arms 58 and 60 to rotate about their respective pivotal mountings on shafts 46 and 54, since the lift bar is engaged in ears 70 and 72 of the arms. The rotational movement of second arm 58 is transmitted through spring 116 to first arm 42, which is thus rotated in the same direction and about the same axis as arm 58. Rotation of arm 42 moves upper roll 34 into engagement with lower roll 22, the two rolls being in parallel, spaced relation prior to movement of arm 42 by elevation of lift bar 78.

The elements are so arranged that upper roll 34 engages lower roll 22 before hook 98 engages latch 102, i.e., before lift bar 78 has reached its fully elevated position. First arm 42 cannot be further rotated in this direction after the rolls are engaged, of course, whereby continued movement of lift bar 78 to the fully elevated position moves only second arm 58. It is apparent that further elevation of ear 70, with arm 42 held stationary, will compress spring 116. Since the position of second arm 58 is fixed once hook 98 is engaged by latch 102, spring 116 will exert a biasing force on first arm 42 which is transmitted to upper roll 34. Therefore, the pressure rolls are biased into contacting engagement with a force dependent upon the rate and amount of compression of spring 116, and the corresponding spring 117 compressed between arms 44 and 60 on the other side of the apparatus.

When lever 134 is moved from the position of FIG. 2 to that of FIG. 3, it may be seen that a thinner portion of cam 112 is positioned for engagement by extremity 92 of finger 88. In other words, the effective radius of lift bar 78 has been reduced in moving lever 134 from the FIG. 2 to the FIG. 3 position. The vertical position of extremity 92 in the elevated position, being defined by engagement of hook 98 with latch 102, is the same, of

course, irrespective of the position of lever 134. The a vertical position of lift bar 78, however, is a function of the effective radius thereof with respect to extremity 92. Since this radius is decreased when lever 134 is moved to the FIG. 3 position, the vertical position of lift bar 78 in the fully elevated position Will be lower than when lever 134 is in the FIG. 2 position by the amount of change in the effective radius due to movement of cam 112.

The above-described condition will be noted from a comparison of FIGS. 4 and 5. The position of extremity 92 of finger 88 is the same in both views. Lift bar 78, and thus ear 70, is somewhat lower in FIG. 5 than in FIG. 4 since the effective radius of lift bar 78 is less in FIG. 5. Spring 116 maintains arm 42 in the position wherein upper roll 34 is in contact with lower roll 22 in both views, whereby the position of arm 42 is the same. Hence, the distance between arm 42 and ear 70 is greater in FIG. 5 than in FIG. 4 with the result that spring 116 is compressed by a lesser amount in FIG. 5. The biasing force urging the pressure rolls into engagement is consequently somewhat less when lever 134 is in the position of FIG. 5 than when the elements are in the FIG. 4 position.

In FIG. 6 is shown, quite schematically, a film unit of the self-developing type to be processed by the abovedescribed apparatus. The firm unit includes tab or leader element 139, to which are attached first and second superposed sheets 140 and 142 with rupturable container 144, carrying a liquid processing agent, positioned therebetween. Before rolls 22 and 34 are brought into contacting engagement with one another, by depression of lever 86 with consequent elevation of lift bar 78, tab 139 is positioned therebetween. Thus, when the rolls are brought together with rotation imparted thereto, tab 139 is engaged between the rolls and the film unitis advanced progressively through the rolls by continued rotation thereof. The compressive force exerted by the rolls due to the spring bias causes container 144 to rupture and release its liquid contents between sheets 140 and 142; as the film unit continues to advance between the rolls the liquid is spread in a uniformly thin layer between the sheets. The relative dimensions of the film unit and processing apparatus are such that the width of the sheets is slightly less than the length of the rolls, although the width of the tab 139, of course, may be considerably less.

In accordance with common and well-known commercial use of such film units and processing apparatus, the first and second sheets of the film unit are normally contained within an opaque envelope, since one of the sheets includes a photosensitive portion in Which a latent image has been formed by photographic exposure in the usual manner and which must therefore be protected from actinic radiation until processing. The opaque envelope may further be contained Within a cassette or the like, of the type commonly used in holding film for radiographic exposures. Means may easily be provided for accommodating a cassette within processing apparatus of the present type, as by providing a horizontally disposed plate or platform between Wall members 10 and 12 in covering relation to shaft and lift bar 78. Thus, as the film unit is advanced through the rolls it withdrawn from both the opaque envelope and the cassette.

Since the photosensitive portion of the film unit must be protected from actinic light, as pointed out above, until processing is completed, it is a common practice to provide a lighttight enclosure or chamber within which the processing apparatus may be enclosed and within which the film unit is discharged from the rolls. Such means are presently in wide commercial use and are fully described in aforementioned US. Patent No. 2,638,828. Thus, the sequence of operations, after exposure of the photosensitive portion of the film unit is to place the cassette in the proper position within the apparatus, place the film unit tab between the rolls, bring the rolls into engagement with one another by depressing lever 86, close the cover or other means provided to insure a lighttight enclosure for the apparatus and film unit, and close the switch supplying power to the roller drive mechanism. After the film unit has been completely advanced through the rolls, power to the drive motor is shut off either manually or automatically by a switch which may be actuated by movement of the film unit. At the end of a predetermined processing period the lighttight enclosure may be opened and the processed film unit withdrawn.

Before another film.unit may be processed in like manner, of course, the elements must be returned from their position of FIG. 4 to that of FIG. 2. This is accomplished by releasing the latch mechanism holding the elements in the FIG. 4 position against the spring bias. Returning to FIGURE 1, there is shown a release lever, numbered 146 and mounted for free rotation about end 84 of shaft 80. Release lever 146 includes manually engageable portion 148 on one side of its pivotal mounting and pin 150 extending laterally therefrom on the other side of the pivotal mounting to a position under arm 152 of latch 102. It may thus be seen that depression of manually engageable portion 148 of release lever 146 will cause latch 102 to move in a clockwise direction, as seen in FIGURE 1, about pin 106 and against the bias of spring 108. Portion 110 of the latch will thus be moved out of engagement with end portion of hook 98, allowing rotation of shaft 80. Springs 116 and 117 may force the ends of first arms 42 and 44 away from the adjacent ends of second arm 58 and 60. The weight of arms 58 and 60 and lift bar 78 will cause the arms to rotate until the lift 7 bar reaches its lower position. This, of course, causes rotation of fingers 88 and 9t and of shaft 80 which is no longer retained by the hook and latch. Springs 116 and 117 maintain the ends of arms 42 and 44 as far from the ends of arms 58 and 60 as permitted by ear 121 on arm 42 and the corresponding ear on arm 44.

The elements are so constructed and arranged that in the elevated position of lift bar 78, as shown in FIG. 4, end portion 123 of plunger 1.24 is still slightly spaced from anvil 126, whereby spring 122 is not compressed. Since the distance between arm 42 and car 76 (and therefore anvil 126) is greater in the FIG. position, end portion 123 of plunger 124 would be spaced from the anvil by a greater distance. However, movement of lever 134 from the FIG. 4 to the FIG. 5 position has rotated plate 118 to a position wherein spacer element 154 thereof is positioned between the free end of the plunger and the anvil. The thickness of spacer element 154 is substantially equal to the change in effective radius of lift bar 73, or, in other words, the difference in the gap between end portion 123 and anvil 126 in the FIG. 2 and FIG. 3 positions of lever 134. Therefore, with lever 134 in the FIG. 3 positions, movement of lift bar 78 to the position of FIG. 5 will result in end portion 123 being slightly spaced from spacer element 154 without compression of spring 122. Hence, the total biasing force urging pressure rolls 22 and 34 into engagement is provided by spring 116 in both FIGS. 4 and 5, with spring 122 opposing separation of the rolls by more than a small amount, but providing none of the biasing force urging them into mutual contact.

It will be noted that the film unit of FIG. 6 is significantly thicker in the portion thereof where container 144 is positioned between sheets 140 and 142. Therefore, as this portion of the film unit is advanced between pressure rolls 22 and 34, the latter tend to be separated with roll 34 being forced upward against the biasing force of springs 116 and 117. With regard to the side of the apparatus shown in FIGS. 25, further compression of spring 116 by upward movement of roll 34 will bring end portion 123 of plunger 124 into contact with anvil 126 or spacer element 154, depending on the position of lever 134. Once this has occurred, both springs 116 and 122 oppose further upward movement of roll 34. Thus, both springs combine to apply a compressive force to the pressure rolls which is considerably greater when that portion of the film unit including container 144 is engaged between the rolls than when the remainder of the film unit is advanced therebetween. This insures a suificient compressive force to rupture and completely squeeze out the contents of container 144 while applying only that compressive force necessary to provide the desired thickness of the liquid layer between the sheets after the container has passed through the rolls. The previouslymentioned slight gap between end portion 123 and anvil 126 (or spacer element 154) allows a slight separation of the rolls by the film unit without compressing spring 122 and thereby increasing the compressive force of the rolls beyond that provided by spring 116.

The amount of compressive force applied to the film unit by the pressure rolls depends, of course, on the amount of compression of springs 116 and 117 which in turn depends on the position of lever 134. In FIG. 7 is shown the internal structure of the mechanism for defining or limiting the first and second position of the lever and the manner of adjustment thereof. A stop which is fixed with respect to arm 58 is provided for limiting the travel in one direction, whereby this may be used as a reference position and travel in the other direction may be limited by an adjustable stop. The fixed stop, designated generally by the' reference numeral 155, comprises first arm 156 which is engaged between ribs 157 and 153 of arm 58 to prevent rotational movement thereof, as may be seen in FIGS. 25. The fixed stop further comprises second m 160, having lip 162 on the lower side thereof,

and opening 164 by means of which the fixed stop is loosely mounted on lift bar 78.

Adjustable stop 166 includes ear 168, radially extending edge 170 and opening 172 through which loosely extends lift bar '78. The position of adjustable stop 166 shown in dot-dash lines in FIG. 7 indicates how car 168 is engaged by washer 174 and retained by screw 176 which is threaded in an opening in second arm of fixed stop 155. The rotational position of adjustable stop 166 may thus be changed with respect to fixed stop 155 by loosening screw 176, rotating the adjustable stop to the desired position and retightening the screw. Fixed pin 178 and detent 180 extend from enlarged annular portion 182 of collar 136, and one shown in solid lines in the positions which they occupy when lever 134 is in its second (FIG. 3) position, and in dot-dash lines numbered 1'78 and 180', when lever 134 is in its first (FIG. 2) position. The position of fixed pin 178 withlever 134 in its first position is extended and numbered 178" and may be seen to be engaged against lip 162 of fixed stop 155. In this position detent 180 is riding on the opposing surface of adjustable stop 166. When lever 134 is moved to its second position detent 180 engages in opening 184 in adjustable stop 166. Any significant overtravel of detent 180 with respect to opening 184 will be prevented by contact of fixed pin 178 with edge of the adjustable stop.

The position wherein adjustable stop 166 is retained will thus determine one of the positions of lever 134 which will in turn determine the compressive force applied to the pressure rolls for the corresponding processing condition. This permits the use of the same mechanical elements interchangeably even though the rate of spring 116, for example, may vary considerably from one apparatus to another due to manufacturingtolerances. It

is also obvious that means may be provided for setting lever 134 in any desired number of rotational positions to provide a corresponding plurality of processing conditions for different types of film units.

It may be seen from the foregoing description that the processing apparatus may be quickly and easily changed from a condition suitable for processing one type of film unit to another condition for processing a second film unit requiring a different thickness of liquid processing agent spread within the film unit by the processing apparatus. Also, compensation may be made for differences in thickness of the film unit components and the additional biasing means provided to act during a portion of the advancement of the film unit to insure complete release of the liquid from the rupturable container wherein it is initially supplied is retained without substantial functional change in both conditions of the apparatus. The movable means used to effect the change in processing condition of the apparatus may be adjusted so that an exact condition may be achieved for a given setting of the movable means despite manufacturing variations in certain components of the apparatus which control said condition. 1

Since certain changes may be made in the above apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is: V

1. Apparatus for effecting rupture of a frangible container of processing fluid in a film unit of the self-developing type wherein said container is positioned between a pair of superposed sheets of said film unit, and for spreading said fluid in a uniformly thin layer between said sheets, said apparatus comprising, in combination:

(a) a pair of elongated, cylindrical pressure rolls between which said film unit may be advanced; (b) first support means for mounting a first of said rolls for rotation about a first, fixed axis;

(c) second support means mounted for pivotal movement with respect to said first support means;

(d) means for mounting said second roll upon said second support means for rotation about a second axis so arranged with respect to said first axis that pivotal movement of said second support means in a first direction moves said second roll toward said first roll in parallel relation thereto;

(e) spring means arranged for movement to a compressed condition wherein said spring means applies a biasing force to said second support means urging the latter in said first direction, the amount of said biasing force being proportional to the amount of compression of said spring means;

(f) manually movable means so arranged with respect to said spring means that the latter are moved to said compressed condition in response to movement of said manually movable means to a first position; and

(g) means arranged between said spring means and said manually movable means and selectively operative to change the amount of compression of said spring means, and thereby said biasing force, when said manually movable means is moved to said first position.

2. The invention according to claim 1 wherein said first support means comprises a rigid frame and said second support means comprises a pair of arms pivotally mounted in parallel, spaced relation upon said frame.

3. The invention according to claim 2 wherein said arms include end portions on each side of the pivotal mountings thereof, said rolls being mounted between one end of each of said arms and said biasing force being applied to the other ends thereof.

4. Apparatus for effecting rupture of a frangible container of processing fluid in a film unit of the self-developing type wherein said container is positioned between a pair of superposed sheets of said film unit, and for spreading said fluid in a uniformly thin layer between said sheets, said apparatus comprising, in combination:

(a) pair of elongated, cylindrical pressure rolls between which said film unit may be advanced;

(b) a rigid support frame upon which a first of said rolls is mounted for rotation about a fixed axis;

(c) a pair of arms pivotally mounted in parallel, spaced relation upon said support frame and having end portions extending on each side of the pivotal mountings thereof;

(d) means for rotatably mounting a second of said rolls between one end of each of said arms, whereby movement of said arms about said pivotal mountings moves said second roll toward and away from said first roll in parallel relation thereto;

(e) first spring means arranged for movement to a compressed condition wherein said first spring means exerts a first biasing force on said arms on the ends thereof opposite said one end in a direction urging said second roll into engagement with said first roll;

(f) movable means for engaging said first spring means and moving the latter to said compressed condition, the amount of compression of said first spring means, and thereby said first biasing force, being a function of the position to which said movable means is moved;

(g) second spring means arranged to exert a second biasing force on said arms in response to movement thereof a predetermined distance away from the position wherein said rolls are in engagement, whereby said rolls are urged toward one another by both said first and second biasing forces;

(it) manually engageable means movable to an operative position to effect movement of said movable means to a position wherein said first spring means is compressed thereby; and

(i) selectively operable means effective to change the position to which said movable means is moved, and thereby the amount of compression of said first spring means, in response to movement of said manually engageable means to said operative position, while maintaining said second biasing force and said predetermined distance substantially constant.

5. The invention according to claim 4 wherein said first spring means are engaged between said arms and said movable means and said second spring means is arranged between said arms and said movable means for compression therebetween by movement of said arms against said first biasing force.

6. The invention according to claim 5 wherein said selectively operable means comprise movable cam means arranged between said movable means and said manually engageable means.

7. The invention according to claim 6 wherein said selectively operably means further comprise spacer means movable with said cam means to provide a surface for engagement by said second spring means upon movement of said arms by said predetermined distance.

References Cited UNITED STATES PATENTS 2 ,638,828 5/1953 Bachelder et a1. -89 2,775,933 1/1957 Maline et a1. 95-89 X 2,873,659 2/1959 Bing et a1. 9513 NORTON ANSHER, Primary Examiner.

F. L. BRAUN, Assistant Examiner. 

1. APPARATUS FOR EFFECTING RUPTURE OF A FRANGIBLE CONTAINER OF PROCESSING FLUID IN A FILM UNIT OF THE SELF-DEVELOPING TYPE WHEREIN SAID CONTAINER IS POSITIONED BETWEEN A PAIR OF SUPERPOSED SHEETS OF SAID FILM UNIT, AND FOR SPREADING SAID FLUID IN A UNIFORMLY THIN LAYER BETWEEN SAID SHEETS, SAID APPARATUS COMPRISING, IN COMBINATION: (A) A PAIR OF ELONGATED, CYLINDRICAL PRESSURE ROLLS BETWEEN WHICH SAID FILM UNIT MAY BE ADVANCED; (B) FIRST SUPPORT MEANS FOR MOUNTING A FIRST OF SAID ROLLS FOR ROTATION ABOUT A FIRST, FIXED AXIS; (C) SECOND SUPPORT MEANS MOUNTED FOR PIVOTAL MOVEMENT WITH RESPECT TO SAID FIRST SUPPORT MEANS; (D) MEANS FOR MOUNTING SAID SECOND ROLL UPON SAID SECOND SUPPORT MEANS FOR ROTATION ABOUT A SECOND AXIS SO ARRANGED WITH RESPECT TO SAID FIRST AXIS THAT PIVOTAL MOVEMENT OF SAID SECOND SUPPORT MEANS IN A FIRST DIRECTION MOVES SAID SECOND ROLL TOWARD SAID FIRST ROLL IN PARALLEL RELATION THERETO; 